Thirty-one years and hundreds of thousands of swims into his life, the undeniable Michael Phelps waited for this night, Aug. 11, 2016, to show the world and give to all of us his most memorable, mind-breaking, totally awing, entirely ridiculous and permanently perfect swim.

Even at an Olympics filled with generation-defining athletes and world records falling by the day, what Phelps did on Thursday night could wind up being the defining moment of the 2016 Rio Games.

For the fourth straight Olympiad, Phelps won the most prestigious event in swimming, the 200-meter individual medley. He is the first person to ever win four straight gold medals in any swim event -- let alone the toughest one -- and in doing so, he defeated his great friend and chief rival, fellow American Ryan Lochte.

Lochte, a tremendous, all-time swimmer in his own right, instantly became an afterthought due to finishing a shocking fifth in the event. Heading into the race, it was a 24-hour buildup as the last swim-off between two American sports icons. It was conceivable, even predicted by some, that Lochte would beat Phelps for the first time at an Olympics in the 200 IM.

Then Phelps went out and showed why Lochte, as great as he's been, doesn't even belong in the same conversation. For Lochte, Thursday's main event was his only individual event in Rio de Janeiro. Like Phelps, he is expected to never compete in another Olympics (though Lochte left the door open Thursday night).

Phelps has owned the swimming world for more than a decade, and he's never been more wowing -- and probably feared -- than right now. At 31, he's supposed to be years past his prime. Somehow, he's managed to stay in it for four straight Olympiads. Phelps' gold medal swim, the 22nd of his indestructible career, finished in 1:54.66, beating out China's Wang Shun (1:57.05) and Japan's Hiromasi Fujimori (1:57.21). Lochte hit the wall at 1:57.47.

NBC swimming analyst Rowdy Gaines said on the broadcast that Phelps' third leg, the 50 meters of breaststroke, was the best stretch of breaststroke he's ever seen Phelps swim. How unlikely -- but how perfectly Phelps of him. At one point, he was pushing past the yellow-line graphic and racing the world record.

"Two things, I guess: I would have loved to break the world record," Phelps said on NBC in reflecting on the achievement. "But winning four in a row, when the announcer said that I had a really hard time pulling it together. It's obviously a very emotional event for me, and it's something that's very special. Being able to win 22 Olympic gold medals, it's something you just dream of. I've said this before, but I'm just living a dream come true."

No one dares dream like this. Phelps has gone beyond imagination and actually lived it, and within American sports has pedaled and pushed his way to eternal status as one of the great athletes in world history. He has 26 medals, 22 of them gold, 13 of them individual. All of those are seemingly untouchable records, the last one set on Thursday, breaking a previous mark set by Leonidas of Rhodes, who was born a couple hundred years before Christ.

Swimming in lane 4 with Lochte shadowing him in lane 5, Phelps trailed Brazil's Thiago Pereira through 50 meters of butterfly. Halfway through the IM, after 50 meters of backstroke, Lochte took over -- barely -- with a .01 lead on Phelps and Pereira.

Then the afterburners came. The world stood up, stepped back and dropped its jaw as Phelps upped his speed and legend over the course of less than 60 stunning seconds. Even for the greatest, this was incredible. By the time Phelps hit his final turn after 50 meters of breaststroke, he was .41 seconds ahead of Pereira and 1.13 in front of Lochte. He emerged from his final turn with a burst and pop, and his splashy freestyle kick pulled him away from the field. This race was a microcosm of Phelps' career. There is no one even close to his stature in the pool.

That freestyle stretch was a handful of seconds that can last for the ages. His separation speed was striking. As others slowed, he fastened. The exception aspect of this race was how Phelps was able to surprise us once more, even being as great as he is. Nobody saw this coming. He won by more than two seconds and a couple of body lengths.

After touching the wall and rallying the crowd inside the Aquatic Center, Phelps didn't flash a smile. Instead, he flashed four fingers, signaling his fourth consecutive gold in the 200-meter IM.

He is the immortal of his sport, and though he's on record as saying this is his last Olympics, expect many to question and implore him as to why that has to be. He's still amazing, now four for four in individual events at these Games. He can be done if he wants to, and he said as much again on Thursday night, but the only other people who'd agree with that decision are probably the ones who have to jump in the pool with him.

"Being able to finish how I want to," Phelps said of why this has been such a successful, emotional week. "I think in 2012, that was something I could say if I walked away then, I wouldn't have been that way. Being able to put in the work and put my body through the pain that it's going through every single race, it's special and this is exactly how I wanted to exit the sport."

This was the signature night of Phelps' career, which is saying something, because he's had a half-dozen classics over the past three Olympics. A mere 38 minutes after winning gold, Phelps was back in the pool to swim the semifinal heat of the 100-meter butterfly. He was in last place 50 meters in -- then touched for second and only lost by one-one hundredth of a second. His time: 51.58.

He'll go for his sixth gold medal of these games in that 100-meter fly on Friday night.

"Hurt," Phelps said of how swimming the 100 fly semifinal felt. "I knew it was going to be painful, but just getting into the final is all I wanted to do."

Phelps readies for exit, having mastered and remastered a sport that he's defined in the process. He can retire at his peak and on his terms if he wants to. But when you're still this great, climbing out of the pool can't be nearly as easy as diving in.

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Phelps has won the 200-meter IM at four consecutive Olympics. USATSI